Date of Completion

2025

Document Type

Thesis

Degree Name

Bachelor of Science in Biochemistry

Keywords

Lemongrass, Antimicrobial

Abstract

The increasing prevalence of multidrug-resistant pathogens, particularly carbapenemresistant Klebsiella pneumoniae (CRKP), poses a significant global health threat. This study explored the potential of Cymbopogon citratus (lemongrass) as a natural antimicrobial agent against CRKP. The research aimed to isolate, characterize, and evaluate the antimicrobial efficacy of the extracted compounds from lemongrass using in vitro methods. The extract was obtained through Soxhlet extraction, purified via Column and Thin Layer Chromatography, and structurally characterized using UV-Visible and Infrared Spectroscopy. UVVis analysis revealed multiple absorption peaks in the 200–400 nm range, particularly within 305.1– 343 nm (Band I) and at 279 nm (Band II), confirming the presence of conjugated aromatic systems consistent with polyphenolic compounds. The CRKP strain used was validated using the CarbaNP test, which showed a positive result for carbapenemase activity. Antimicrobial efficacy was assessed via Agar well diffusion, Minimum Inhibitory Concentration (MIC), and Minimum Bactericidal Concentration (MBC) tests. The most potent fraction exhibited an MIC of 8.90 µg/mL but lacked bactericidal activity. Further assays revealed biofilm disruption in a dose-dependent manner with an inflection point at 7.225 µg/mL, and ROS inhibition at higher concentrations suggested antioxidant activity. The study concludes that the semi-purified C. citratus extracts exhibit promising bacteriostatic, anti-biofilm properties, and antioxidant properties against CRKP. It is recommended that future researchers pursue advanced compound isolation, in vivo studies, synergy testing with antibiotics, and broader spectrum analysis to develop viable plant-derived antimicrobial therapies.

First Advisor

Walter Aljohn T. Espiritu, RCh

Download

Share

COinS